The purpose of this study is to establish breeding systems for producing healthy Aotus, Saimiri, Saguinus, and Cercopithecus animals in a consistent manner for research investigators at NIH and other interested scientists. Basic reproductive parameters being studied include duration of gestation, male and female reproductive cycles, relationships of accessory sexual organs to sexual activity, male-female breeding ratios, reproductive hormone serum levels, puberty changes, infant development, and minimum reproductive age.